Note: Descriptions are shown in the official language in which they were submitted.
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B~CKGROUND AND SUM~ARY OF T~E INVENTION
The present invention is an improvement in a locking
device for preventing an unintended movement of the slide gate
door of a railway hopper car from the closed to the open pO3 i -
tion. Various devices for accomplishing this purpose are knowrt
to the art, as for exampleg U. S. Patents 2,142,236~ 2,749~851
and 3~707~126.
one advantage of the present invention as compared to
the known devices is that the locking davice has some resiliency
in resisting a force tending to mo~e the slide gate door in the
opening direction. Railway cars are s~bjected to nttmerous im-
pact forces, some of which are quite severe. For exampleD when
a railway car moves down the ht~p in a classification yard it
likely will impact upon other cars on ~he track ahead of it and
the impact can be exceedingly forceful. While shock absorbers
are bui1t into the coupLing units of cars, still ther~ are severe
shock loads within the body of the car and its content. SUch
shock loads cctn affect the position of the slide gate door due
to its inertia, with the slide gate door thus impacting against
its locking device (depending upon the sense of the shock force~.
The present invention makes available a construction in which
there need be no play, or lost motion, when the slide gate door
is locked closed, and which includes a spring element to absoxb
shock forces applied in the senqe of the door opening directionO
Anoth~r advantage o the invention is the ~implicity
ava1lable to obtain a good fit during the course o manufacture.
As compared to the available state of the manufacturing art, the
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manufacturing techniques employed in producing railroad hoppercars and their components are not very -qophisticated, perhap~
even crude. That is, in the main the components are not made
with very close tolerances because such criticality is quite
unnecessary and the expense of achieving close tolerances is
unjustified. The application is such that the monetary savings
achieved by usiny forming and fabricating techniques which do
not result in close tolerances is importan~. Through the use
of the present invention i~ is quite simple for the worker~ who
are put~ing the car together to make adjustments necessary to
achieve a good fit even though the tolerances up to that point
have been sufficiently loose such that it would be only by
accident that a good fit was achieved.
Further objects and advantages will become apparent
from the disclosure herein of an embodiment of the invention.
In the present i~vention a plate is imposed betwePn
the leading (in the opening sense) edge of the slide gate door
and a cam pivotally mounted on the car frame, which plate is
positioned and arranged to serve as a spring. The plate is
welded to that edge of the door and the plate's distal side is
located slightLy above the door supports. That part of the cam
face that engages the distal side of the plate is arranged to
cam the plate toward those supports, wheraby the pla~e is bloclced
against significant movement ln the door opening direction~ and
serve~ as a spring resisting forces applied in the sense o~ the
door opening direction.
DESCRIPTION OF ~HE DRAWINGS
Figure 1 is an elevational view, partially broken away,
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of a segment of a railway hoppcr car, which segment includes a
portion o~ the slide gate door, and shows an embodiment of the
invention in the door unlocked position;
Figure 2 is a view similar to Figure 1 showing the
door partially open;
Figure 3 is a view similar to Figure L but showing
the doox in the closed and locked pos ition9
- ~ Figure 4 is a view similar to ~igure 3 but showing,
in exaggerated form, what occurs when a force is applied to
the s lide gate door in the sense of uxging the door toward the
open position;
Figure 5 is a partial section as viewed at line 5-5
of Figure 4; and
Figure 6 is a view corresponding to Figure 5J but
iLlustrating a modification.
DESCRIPTION OF SPECIFIC EM:BODIME~T
The following disclosure is offered for public dis-
semination in return ~or the grant of a patent. Although it
is detailed to ensure ade~uacy and aid und~rstanding~ this is
not intended to prejudice that purpose o~ a patent which is to
cover each new inventive concept therein no matter how others
may later disguise it by variations in form or additions or
further improvements.
A railway hoppe.r car slide gate will include a ~rame,
generally 10. The loading space or bins (not shown) o~ a rail-
way hcpper car have a downwardly extending chute through which
the lading can be discharg0d. At the bo~tom o~ the chute are
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the angled sides 11 about the opening 12 through which the car's
contents are discharged, A slide gate door 13 is employed to
closa off this opening. This door resks upon supports 14 formed
by a part of the frame 10~ To move the door along the supports
between the closed position and the opened position, the door
has a pair of racks 16 secured to the underside thereof. ~ach
rack is engaged by a pinion 17 secured to a shaft 18 in the
frame. Means such as a handle 19 is provided for rotating the
shaft 18 by use of a removable lever l9a or power tool and thus
causing the pinion, by engagement with the rack, to move the
door in the opening or closing direction. Various means are
employed to provide a seal about the gate when it is in the
closed position. Such means may include an upturned f lange or
edge 21 which abuts a stop 22 when the door is in the closed
position (Figures 1 and 3).
As thus far described, the stxucture is co~ventional
and the details thereof are merely or the purpose of illustra-
tion.
In the present invention a plate ~5 is employçd. The
plate has a proxLmal side 25a which is welded to that edge of
the gate 13 which is the leading gate sida as the gate moves in
the opening direction, i.e., to edge 21. The positioning of
the plake is such that the distaL side 25b of the plate is a
short distance ~e.g., one-quarter of an inch or so) above the
door supports 14 when the plate i5 in the free condi~.ion tFigures
1 and 2).
This plate cooperates w.ith at least one cam 2G but
preferably with a pair of cams 26 to lock the slide gate door
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in the closed positionO only one of cams 26 is illustrated,
but normally there would be a second one at the opposite side
of the door from that illustrated. Both of these cams are
secured to a shaft 27 for movement in unison. Shaft 27 is
journaled in brackets 28 forming a part of the frame 10~ ThiS
cam has a peripheral face (best seen in Figure 5), significant
portions of which are identified in the drawings as 26a-d. The
cam has an opening 26e which, when the door is locked closed
~Figure 3), registers with an opening 28a in bracket 28. This
permits a car seal 29 to be inserted through both openings.
~hus the seal must be broken before the gate may be opened and
the presence of an unbroken seal signifies that the car's con~
tents are intact.
Figure 3 illustrates the door in the closed and locked
position. At this time the distal side 25b of the plate is
bearing against the portion 26a of the cam face. This prevents
the door from significantly moving in the opening direction
(i.e., toward the right in the drawings). Assuming that a
strong force would be applied to the ~lide gate door tending to
mo~e the door in the opening direction, the cam's reaction to
that force is almost in line with the axis of shaft 27. In
Figure 4 the line 33 represents a tangent to the curve oE the
portion 26a of the cam at the area of contact between the cam
face and plate edge 25b. Line 34 is normal to the tangent line
33 and represent~ the force that the edge 25b is applying against
the cam ~the reaction force of the cam being diametrically oppo-
site)~
Figure 4 iLlustrates, with some exaggeration, the
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situation that occurs when an extremely strony force is applied
to the door 13 in the sense of the door opening direction~ The
side 25b of the plate is cammed by the portion 26a of the cam
in a downward direction with that movement ultimately being
prevented by edge 25b '5 con~act with ~he suppor~s 14. The plate
is now flexed and acting as a spring. This spring action wilL
permit a limited amount o~ movement of the slide gate door in
the opening direction, resulting in the gap 35 betwe~n the edge
21 of ~he door and the ~top 22. For emphasis it will be repeat-
ed, that Figure 4 is an exaggerated illustration. The stiffness
of plate 259 along with the:friction occurring in the camming,
is such that under normal conditions the movement of the slide
gate door and the plate to the right will terminate before the
side 25b o~ the pLate comes into contact with the support L4~
of courseS when the force causing the impetus ~oward door dis-
location is removed, the spring action of the plate 25 will
return the door and plate to the Figure 3 pO5 ition.
Assuming that the door is to be opened to permit the
car's contents to be discharged through the opening 12, the
first step would be to remove seal 290 The cams 26 are then
rotated to the Figure 1 position. This may be done by grasping
the projection that defines portion 26c and rotating it clock-
wise from the Figure 3 position as indicated by arrow 38 In
the normal manner shaft 18 i5 now rotated clockwise orcing
slide gate door 13 and plate 25 to the right. As this is done,
the distal side 25b of the plate contacts the projection forming
portion 26c. ThiS rotatas the cam counterclockwise as indicated
by arrow 39. I~ will be noted that the part of the cam fo~nin~
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portions 26b, 26a and 2Gd is substantially larger~ and thus sub-
stantially heavier~ than is the remainder of the cam. As this
heavier part of the cam gets to the left of a plane vertically
through the axis of shaft 27 (during the opening movement of the
slide gate door~, the weight thereof causes the cam to flop in a
counterclockwise direction so that the portion 26d of the cam
then is resting on the plate 25 as illustrated in Fi~ure 20 The
cam essentially remains in this position during the remainder of
the opening of the door, and also aq the door returns to the
Figura 2 position. As the door continues to move in the cLosing
direction (to the left) from the Figure 2 positio~ it will uLti-
mately get to a location at which the distal side 25b of the
plate passes the portion 26d of the cam. When this occurs, the
weight of the heavier side of the cam urges the cam in the
counterclockwise direction so that the cam automatically rotates
toward the Figure 3 position. The cam 26 has surface 26e which
is arranged so that it is radiaLly nearer to cam pivot point at
shaft 27 than surface 26a. This allows the cam to sel-engage
to this position when the door is closed. To engage the cam to
the fully closed position, as shown in Figure 3, with cam sur-
face 26a and plate 25 in contact, an external counterclockwise
torque is required on the cam 26. This enga~ing external torque
preloads the lock by deflecting plate 25 partiall~ down. Ulti-
mately the portion 26b of the cam will be resting on the upper
surface of the plate 25. The door is ayain locked in the closed
position (whether or not a seal 29 or its equivalent is empLoyed).
From the foregoing description it is beLieved that
those skilled in the art will be apprised of th~ simplieity
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available to produce a satisfactory ~it of the locking device
and the sli.de gate door even though the components are not
formed to very precise tolerances. For example, a jig may be
employed to hold door 13 and plate ZS while they are welded SQ
that the location of edge 25b is reasonabLy accurate~ Similarly,
a jig may be employed in the mounting o~ brackets 28 so that
shaft 27 will have the deqired position. If even through the
use of such jigs lor if even less accurate positioning of parts
is employed~ the desired final fit is not achieved, it is a
sLmple matter to make plate 25 slightly oversize and then grind
off a small portion of edge 25b after final assembly and thus
achieve the desired fit.
Although plate 2 5 i5 shown in Figure 5 as a or~e piece
unit extending transvexsely, relative to the direction of travel
of the gate, and being engageable with one or more of ths cams
as herein describsd9 econ~mics of manufacture may re~uire the
plate to be in several parts, each part approximately one inch
wide in the transverse dimension to constitute a finger and each
part being engageable wi~h a cam. Such a partial plate lor
fingex~ is sh~wn at 25' in ~igure 6.
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